In a positioning control of moving a target object to a target position using a motor for power, at a point of time at which output of a position command value is terminated, the target object has not reached the target position yet, and a position deviation occurs. Therefore, a time proportional to the reciprocal of a proportional control gain Kp with respect to the position deviation is necessary before the target object moves to the target position and the position deviation settles to “0”.
A method of shortening a time (settling time) necessary for a positioning control by making a value of the proportional control gain Kp large is disclosed. However, when the proportional control gain Kp is set to a large value, a positional response becomes vibratory, and thus the settling time is lengthened inversely.
Accordingly, a technology of shortening the settling time while preventing the response from being vibratory by switching the value of the proportional control gain at a point of time at which the output of the position command value is terminated is suggested (PTL 1).